Hot tops for ingot molds



Aug. 20, 1963 c. MARIE ETAL HOT TOPS FOR INGOT MOLDS Filed March 3, 1961 United States Patent 3,100,921 HUI TGPE; FGR lNGOT MOLDS Claude Marie and Rene Thierzy, Corheil-Essonnes,

France, assignors to Societe a Responsabilite Limitee Doittau Pioduits Metallurgie, Corbeil-Essonnes, France, a corporation of France Filed Mar. 3, 1961, Ser. No. 93,102 Claims priority, application France Mar. 7, 1966 3 Claims. (1. 22-147) Various types of hot tops for ingot molds are known which are positioned at the upper end of the ingot mold and are intended to receive a certain amount of molten metal forming a deadhead or runner which feeds the core of the ingot during its solidification. In order to allow the use of the ingot mold for ingots of different volumes, hot tops of the reentering or shiftable type are used which may be caused to sink to a variable extent into the ingot mold. Two modus operandi are then possible, to wit: either the hot top is held fast in position during the solidification of the ingot and the cooling of the ingot, so that the shrinkage is balanced only by the formation of the runner, or the hot top is allowed to float and to sink gradually inside-the ingot mold during the solidification of the ingot. Now, my invention has for its object a hot top of this type which is adapted for use in accordance with either of the two techniques which have just been referred to.

Shiftable hot tops, as generally resorted to, are constituted by a peripheral metal frame provided with an inner lining of refractory material, whether heat insulatan element such as a thin metal blade forming a packing between the hot tops and the wall of the ingot mold, said element being adapted to initiate the solidification of the molten metal which has crept through the gapbetween the metal Walls of the hot top and of the ingot mold respectively.

These shiftable hot tops show various drawbacks, to wit: a lengthy and costly preparation of the packing, the brittleness of the annulus at the lower end of the frame, which annulus is made of refractory material, the necessity of renewingsaid annulus at each casting, a delicate molding as required, in order to prevent the shocks between the annulus and the wall of the ingot" mold, a sub stantial offset along the line of connection between the ingot mold md the runner as a consequence of the crosssection required for'the refractory annulus and of-the partial or complete adherence of the ringtothe lower end of the runner, which adherence is increased by the burrs formed by the metal creeping through the gap between the ingot mold and the hot top, which may lead to the objectionable inclusion of refractory material, which is highly detrimental to the rolling of the ingots obtained.

My invention has for its object, while retaining and even improving the advantages inherent to the abovereferred to type of hot tops to wit: the possibility of casting ingots of different weights, the cutting out of any burr, the reduction of the wear at the upper end of the ingot molds and the reduction of the losses of heat in a lateral direction to reduce or even cut out at least part of the above-mentioned drawbacks.

My invention has for its object a method for forming the packing of a hot top of the type considered after introduction of the hot top inside the ingot mold through extrusion of the head of material having a plasticity arice between said parts, and which is driven laterally out so as to form the packing between the hot top and the ingot mold.

According to a preferred embodiment, the hoop is sufficiently heavy for its weight to ensure the compression and the extrusion of the material forming the packing and to oppose the ferrostatic thrust exerted on said packing, its own weight being added to that of the frame, so as to balance the general static thrust exerted by the molten metal. An arrangement of stops limits the vertical rising movement of the hoop with reference to the frame and hoisting means for the whole hot top'system are provided on the hoop, while the frame is in its turn provided with lateralsupports which allow setting it at the desired height inside the ingot mold. a

The frame of the hot top may be provided with any conventional inner refractory lining, whether heat insulating or exothermic, for instance of the type described in the French Patents No. 1,084,725 of June 12, 1953, No. 1,112,520 of October 11, 1954, or No. 1,112,966 of October 21, 1954. v

The material which is to form the packing may be made of any substance provided with a sufficient plasticity to allow its extrusion under the weight of the hoop or under the action of thrust-producing means inserted between the frame of the hot top and the hoop. it is possible, in particular, to resort to a siliceous, aluminous, magnesian limestone, lime-containing, carbide-containing or the like grount, or else,to refractory or melted cements, putti es of the type sold in trade and various agglomerated mixtures incorporating the above mentioned refractory products with the addition of vegetable or mineral oils, mealy or starchyproducts, residuary paper pulp, sugarcontaining products, natural or synthetic resins, cement, sodium silicate and the like.

Said pasty material may be incorporated throughdirect introduction into the space which it, is to occupy Tand'which is open to its maximum between, the edge of ,theshrinkage hole frame and the-lower end of the loop,-but it is also possible to introduceit in the form of elongated elements of a predetermined outline forming round, square or rectangular bars, which bars are then fitted inside the gap considered; the matenialrnay, if'it is naturally too plastic to form a rigid structure, be infroduced into woven or extruded sheathsmade of metalQtextile material, syn thetic resins, asbestos or the like, the cross-sectionof the sheath being irrelevant.

Our invention has also for its object the plastic material adapted to form packings in accordance with the method disclosed in association with the above-described hot tops.

We will now describe an embodiment of our improved hot top, reference being had to the accompanying drawtings, wherein:

FIG. 1 is a partly elevational, partly sectional view of a hot top according to the invention, as positioned before the hoop is lowered over it.

FIG. 2 is a view similar to FIG. 1 showing the arrangement after the hoop has been lowered.

In said drawings, 1 designates the upper section of the ingot mold. In the opening of the latter, there is inserted the lower end of the frame 2 of the hot top, which frame is constituted by a metal wall in the shape of the fnistum of a pyramid or the like and is provided with an outer flange 3 along its lower edge, of which flange the periphery is fitted inside the opening of the ingot mold with a clearance e corresponding to the clearances generally allowed floating or shiftable hot tops. 7

inwardly, so as to protect the upper portion of the lining 5 of the hot top. The inner surface of the wall 2 is pro: vided with ribs which are not illustrated and-to which are secured, through gluing or otherwise, exothermic plates forming said inner lining 5, which lining does not form part of the present invention and may be of any known type whatever, so that it need not be described with any further detail.

Round the wall 2 forming the frame of the hot top, there is mounted a metal hoop 6 adapted to move vertically within a limited range. Said hoop is guided by elongated slots 7 formed therein and engaging radial arms Srigid withthe outer wall of the hot top 2, which anns form the supports of the latter resting on carrier blocks 9 defining, at leastun-til the casting is performed, thedepthv of engagement of the hot top inside the ingot mold; The hoop 5 carries furthermore lateral trunnions 10 through which it may be hoisted and lowered.

element made of a material having a sufiicient plasticity,

say an edge-ringer bead 11 made of one of the above! mentioned substances and preferably, in practice, of thick silicate-containing grout or of putty.

The arrangement'is then allowed to sink inside the ingot mold 1' until the'arms or supports Brest on the carrier blocks 9, of which the height is selected in conformity with the weight of the ingot to be cast (FIG. 1); from this moment onwards, only the hoop continues sinking and its weight compresses the head 11 and urges the materialforming the latter outwardly. It constrains thus 1 said'material to enter the clearance e between the periphery oflthe flange 3 and the lower end' of the hoop 6. It is apparent, from inspection of FIG. 2, that the bead material 'll provides a perfect packing and, if the volume of the head is suitably selected, the lower edge 12' of the deiiormed packing extends into proximity with the 1 lower surface of the flange 3 on the'frame 2, which limits the formation of burrs to a maximum.

a It is then possible to cast the metal and, after the casting, the blocks 9 are removed if the hot top'is used in accordance with the procedure usually resorted to for 'Ihe above-described embodiment illustrated by way of example may be modified in' many manners without unduly wideningthe scope of the present invention which covers generally all'the ingold molds in which the packing is formed through extrusion of a mass having plasticity.

What we claim is: 1. A hot top for operation with an ingot mold, comprising a metal frame provided with an outer peripheral flange at its lower end, the cross-section of which correspondswi-th a clearance to the size required for it to engage the opening of the ingot mold, a hoop surrounding the frame and shiftable vertically over the latter down to a position leaving a small gap between its lower edge and the flange on the frame, and a head in the gap between said lower edge of the hoop and the flange and adapted to be crushed and driven outwardly by the lowering of said hoop over the frame :to form a packing between the latter and the opening of the ingot mold.

2. A hot top for operation with an ingot mold, com

flange at its lower end, the cross-section of which corresponds with a clearance to the size required forit to engage the opening of the ingot mold, a hoop surrounding the frame and shiftable vertically over the latter down to a position leaving a small gap between its lower edge and the flange on the frame, and a head in the gap between said lower edge on the hoop and the flange and adapted to be crushed and driven outwardly by the lowering 'of said hoop over the frame to form a packing between the latter and the opening of the ingot mold, the weight of the hoop ensuring the compression and the extrusion of the material forming the beadand opposing the ferrostatic thrust exertedthrough the gap on the compressed head, the,

added weight of the hoop and of the frame balancing the 3 A hot top for operation with an ingot mold, com,- prising a metal frame provided with an outer peripheral flange at its lower end, the cross-section of which cor-responds with a clearance to the size required for it to engage the opening of the ingot mold, a hoop surrounding the frame and shiftable vertically over the latter down to a position leaving a small gap between its lower edge and the flange on the frame, -a head in the gap between said lower edge of the hoop and theflange and adapted tobe crushed and driven outwardly by the lowering of said hoop over the frame to form a packing between the latter and adapted to rest to allow the sinking of the'lo'wer edge of the hoop. intoengagement with the bead.

'References Cited in theifile of this Patent 7 UNITED STATES PATENTS. 2,231,813 r 2,863,192 Kautlman Dec. 9, 1958 McDonald r Feb. 11, 1941 

1. A HOT TOP FOR OPERATION WITH AN INGOT MOLD, COMPRISING A METAL FRAME PROVIDED WITH AN OUTER PERIPHERAL FLANGE AT ITS LOWER END, THE CROSS-SECTION OF WHICH CORRESPONDS WITH A CLEARANCE TO THE SIZE REQUIRED FOR IT TO ENGAGE THE OPENING OF THE INGOT MOLD, A HOOP SURROUNDING THE FRAME AND SHIFTABLE VERTICALLY OVER THE LATTER DOWN TO A POSITION LEAVING A SMALL GAP BETWEEN ITS LOWER EDGE AND THE FLANGE ON THE FRAME, AND A BEAD IN THE GAP BETWEEN SAID LOWER EDGE OF THE HOOP AND THE FLANGE AND ADAPTED TO BE CRUSHED AND DRIVEN OUTWARDLY BY THE LOWERING OF SAID HOOP OVER THE FRAME TO FORM A PACKING BETWEEN THE LATTER AND THE OPENING OF THE INGOT MOLD. 